Fuel-injection device for internal-combustion engines



April 2 8, 1931. y 0 s s 1,802,933

FUEL INJECTION DEVI-CE FOR INTERNAL COMBUSTION ENGINES Filed Aug. 3, .1929

INVENTDI pqrrm N 5% Patented Apr. 28, 1931 UNITED STATES PATENT OFFICE EDUABD V011 SALIS, OF WINTERTHUR, SWITZERLAND, ASSIGNOB TO THE SULZER FBERES SOGIETE ANONYME, OF WINTERTHUR, SWITZERLAND FUEL-INJECTION DEVICE FOR INTERNAL-COMBUSTION ENGINES Application filed August 3, 1929, Serial No. 888,805, and in Switzerland August 10, 1928.

containing the locking piston, the pressure in this chamber being released by opening a relief valve in the fuel supply pipe or 1n the fuel pump itself.

According to this inventionthe pressure chamber containing the locking plston is in constant communication with the charge accumulator through a throttle-controlled ipe and the outlet from the ressure chamer is intermittently opened y means of a control gear, fuel being continuously supplied to the charge accumulator by the fuel One construction according to this invention is somewhat diagrammatically illustrated by way of example in the accompanying drawing, the injection device shown being of a type suitable for use with an internal combustion engine in which the fuel is injected into the engine cylinder at the ignition dead centre of the engine piston.

Referring to the drawing, the injection device comprises a casing a to which fuel is supplied by a pipe 0. The casing contains a needle valve 7) provided with a conical head at forming a piston against which the pressure of the fuel in the casing acts to lift the valve when the latter is released. The charge accumulator comprises an annula-r piston e which is concentric with the needle valve 6 and is held down on a shoulder of the needle valve by a compressionspring f. The upper end of the needle valve 6 is in the form of a piston and projects into a chamber 9 which is incommunication on one side with the accumulator through a pipe k having a throttle-controlled opening a and on the other side through a pipe is having a control gear adapted to open the outlet pipe is at the moment when injection is to take lace. a

The e1 supplied through the pipe 0 raises the annular piston e and so compresses the spring 7. Some of the fuel passesby the pipe 12. through the throttle valve 71 to the chamber 9 where' ressure is built up and acts on the piston ormed bythe upper end of the needle valve 1) so as to maintain the latter in its closed position.- Assuming that the engine piston has at this point reached the ignition dead centre, the control gear opens the outlet pipe Ir: and releases the pressure in the chamber 9 thus permitting the needle valve 1) to lift under the pressure of the fuel in the accumulator.

The annular iston 0 now descends under the pressure 0 the spring f to inject the fuel into the cylinder and at the end of the injection stroke the annular piston e reengages with the shoulder on the needle valve b and thus returns the valve to its seating,

in'ection being then complete.

e a certain amount of fuel will pass through the throttle valve z into the chamher 9 during the injection stroke of the annular piston a, this quantity is by reason of the short time available for its passage not appreciable, and may in any case be compensated by increasing the output of the fuel pump. It will be readily understood that as the chamber 9 is-connected to the fuel accumulator through a throttle valve, the locking of the needle valve and accumulation and injection of the fuel can be controlled by a' single control member disposed,

if desired, at a distance from the apparatus and in this way the operation of the device V can be rendered much more reliable.

It will be appreciated that the construe-- I claim:

In a fuel injection device for internal combustion engines the combination with a valve casing, of a fuel injection valve, an accumulator chamber on the exit-end of the injection valve, a pressure chamber on the other end of the injection valve, means for supplying the fuel under pressure to the accumulator chamber, a connecting pipe between the accumulator chamber and the pressure chamber, a throttle valve in this connecting pipe, an outlet from'the pressure chamber, a valve closing this outlet and means for opening the 7 outlet when fuel injection is to commence.

In testimony whereof I have aflixed my signature.

EDUARD VON SALIS. 

